20887993 has 8 divisors (see below), whose sum is σ = 23914880. Its totient is φ = 17871840.

The previous prime is 20887967. The next prime is 20888003. The reversal of 20887993 is 39978802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20887993 - 2²¹ = 18790841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20887903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2053 + ... + 6781.

It is an arithmetic number, because the mean of its divisors is an integer number (2989360).

Almost surely, 2^20887993 is an apocalyptic number.

It is an amenable number.

20887993 is a deficient number, since it is larger than the sum of its proper divisors (3026887).

20887993 is an equidigital number, since it uses as much as digits as its factorization.

20887993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5367.

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 20887993 is about 4570.3383900976. The cubic root of 20887993 is about 275.4010369157.

It can be divided in two parts, 2088799 and 3, that added together give a palindrome (2088802).

The spelling of 20887993 in words is "twenty million, eight hundred eighty-seven thousand, nine hundred ninety-three".